Small elastomeric stoppers are commonly used to seal small volume medical containers such as glass unit dose vials. Due to the inherent resiliency of the elastomer, a sharp piercing device such as a needle or a cannula is used to penetrate the stopper to allow fluid communication from the sealed container. The solution or drug can then be transferred for administration to a patient or addition to another medical container.
The majority of stoppers currently in use are molded of medically suitable elastomeric compounds that allow entry by a sharp piercing device. These stoppers are configured so that the elastomeric material reseals when the sharp entry device is withdrawn. However, the thick diaphragm configuration of these conventional stoppers is not suitable for blunt connection devices. A blunt device would require excessive force to be applied to penetrate the thick diaphragm stoppers currently in use.
With increasing concern about diseases such as HIV and AIDS, the use of sharp entry devices in the healthcare environment is being actively decreased. "Sharps" have the potential to accidentally breach the skin barrier by a "needle stick" and thereby transmit disease.
For fluid flow applications, such as for IV solution administration, a blunt cannula device, such as the Lifeshield.RTM. Blunt Cannula, can be used with a pre-pierced septum, such as the Lifeshield.RTM. Prepierced Reseal, both sold by Abbott Laboratories. However, the same pre-pierced construction used in pre-pierced reseals cannot be implemented for the stoppers on vials because of sterility and shelf-life degradation questions.
As an alternative to pre-pierced stoppers, there are known stopper constructions with thin diaphragm portions. However, these known thin diaphragm stoppers are typically special use stoppers and have inherent limitations for general use, such as expense, risk of contamination or lack of resealability, for example.
A stopper formed of a low tear-resistant rubber with a conical well in the top face that extends partway into the plug portion of the stopper is disclosed in U.S. Pat. No. 2,906,423 to Sandhage. The stopper also has a cut slit extending partway from the apex of the conical well towards the bottom face of the stopper. This construction provides a moisture proof closure as well as a closure that can be entered by forcing a blunt plastic needle therethrough. However, the stopper of Sandhage with the concavity and slit on the top or entry surface is difficult to swab with an antiseptic agent prior to entry and therefore increases the risk of introducing potential contaminants into the vial. Also the expense of manufacturing and maintaining quality control for the multiple steps in the molding, slitting and cleaning of the Sandhage stopper would be prohibitive for other than a special high cost vial.
The use of a transverse slot or multiple slots to thin a stopper diaphragm for entry by a blunt device such as a male luer connector is disclosed in U.S. Pat. No. 5,060,812 to Ogle. However the manufacturing and assembly processes are complex and thus expensive and the top concavity creates potential swabbing and contamination problems.
A stopper with a thin diaphragm portion including an indentation in the top surface is disclosed in U.S. Pat. No. 3,653,528 to Wimmer. This stopper also has swabbing problems and further would be difficult to reseal. Entry by a blunt device would tear the diaphragm along the conical wall portion and there would be little radial compressive forces to assist in resealing the diaphragm once the entry device is withdrawn.
Thus, it is an object of the present invention to provide a stopper assembly that is usable with blunt entry devices for sterile access to small volume vials or ports for flexible containers.
It is another object of the present invention to provide a stopper assembly which is economical to manufacture, assemble, sterilize and package.
Another object of the present invention is to provide a stopper which does not require excessive force by the user to insert a blunt entry device.
Another object of the present invention is to provide a stopper assemble for use by a blunt entry device which reseals after the entry device is withdrawn, thus potentially allowing for multiple entries.
These and other important objects will be apparent from the description of the present invention which follows.